Herbicidal composition and method employing pyridine derivatives

ABSTRACT

NITROAMINOPYRIDINES AND THEIR USE AS HERBICIDES.

United States Patent 3,806,333 HERBICIDAL COMPOSITION AND METHOD EM-PLOYING PYRIDINE DERIVATIVES Karl Ayad, Wrexham, Wales, assignor toMonsanto Chemicals Limited, London, England No Drawing. Originalapplication Apr. 2, 1969, Ser. No. 812,890, now Patent No. 3,634,439.Divided and this application Feb. 16, 1971, Ser. No. 115,845

Int. Cl. A01n 9/22 U.S. Cl. 71-94 3 Claims ABSTRACT OF THE DISCLOSURENitroaminopyridines and their use as herbicides.

This application is a division of application Ser. No. 812,890, filedApr. 2, 1969 now US. Pat. No. 3,634,439.

This invention relates to nitroaminopyridines and their use asherbicides.

In accordance with this invention it has been found that the growth ofgerminant seeds, emerging seedlings and established vegetation can becontrolled and modified by exposing the seeds, emerging seedlings or theroots or above-ground portions of established vegetation to the actionof an effective amount of one or more of a nitroaminopyridine selectedfrom the group consisting of h. N i a wherein R is selected from thegroup consisting of halogen, alkyl having a maximum of six carbon atoms,trichloromethyl, trifluoromethyl, alkenyl having a maximum of fourcarbon atoms, hydroxy, alkoxy having a maximum of six carbon atoms,mercapto, alkylthio having a maximum of six carbon atoms, cyano,carboalkoxy having a maximum of six carbon atoms and sulfino; R and Rare each independently selected from the group consisting of hydrogen,alkyl having a maximum of four carbon atoms, alkanoyl having a maximumof six carbon atoms, alkylsulfonyl having a maximum of four carbon atomsand phenylsulfonyl; n is an integer 0 to 2; x is an integer 1 to 2;provided that when NR R is in the 2-position, N0 is in the 3-positionand R is hydrogen or in the 5- position then R and R are each selectedfrom the group consisting of hydrogen, acyl having a maximum of sixcarbon atoms, alkylsulfonyl having a maximum of four carbon atoms andphenylsultonyl provided that both R and R are not hydrogen;

(b) Addition salts of the compounds defined in (a), said addition saltsbeing selected from the group consisting of hydrochlorides,hydrobromides, oxalate, sulfate, benzenesultonate and the alkyl halideshaving a maximum of tour carbon atoms; and

(c) The N-oxide of the compounds defined in (a).

The preferred compounds of this invention are the pyridine bases definedin section (a) above.

Preferred compounds are also compounds of the formula )n NRl l wherein Ris selected from the group consisting of alkyl having a maximum of fourcarbon atoms and halogen; R is hydrogen and R is selected from the groupconsisting of acyl having a maximum of four carbon atoms andphenylsulfonyl.

Still further preferred compounds are of the formula h NHR,

wherein R is alkyl having a maximum of four carbon atoms; R is selectedfrom the group consisting of hydrogen, alkanoyl having a maximum of sixcarbon atoms, alkylsulfonyl having a maximum of four carbon atoms andphenylsulfonyl, n and x are each integers 1 to 2, provided that when Ris hydrogen and n and x are both 1 then R is in a position other thanthe 5-position.

The preparation of the nitroaminopyridine of this invention is byconventional means, such as the action of fuming nitric acid on thecorresponding aminopyridine in the presence of concentrated sulfuricacids. The reaction may initially result in the formation of the nitro--aminopyridine which rearranges to the nitroaminopyridine compound.

The addition salts are easily prepared by the reaction EXAMPLE 1 Thisexample describes the preparation of 5-nitro-6-methyl-Zacetamidopyridine.

A mixture consisting of 10 grams 5-nitro 6methyl-2- aminopyridine, 37ml. glacial acetic acid and 37 ml. acetic anhydride was heated at refluxtemperature for 4 hours. After cooling to room temperature, the liquidwas added to crushed ice and the acid neutralized with solid sodiumbicarbonate. The solid which separated was removed by filtration, washedwith a small amount of water and dried. Recrystallization from anethanol water solution gave a solid melting at 195 C.

Calcd. for C H N O (percent): C, 49.3; H, 4.61; N, 21.6. Found(percent): C, 48.8; H, 4.7; N, 21.4.

EXAMPLE 2 This example describes the preparation of 3,5-dinitro-6-methyl-2-aminopyridine and its :acetyl derivative.

Five (5) grams of 3-nitro-6-methyl-2-nitroaminopyridine, prepared fromthe action of nitric acid on 3-nitro-6- methyLZ-amiriopyridine, wasadded to 25 ml. concentrated sulfuric acid. The resultant mixture isheated on a steam bath for 40 minutes yieldingly a clear yellowsolution. After cooling to room temperature, the solution is added tocrushed ice and the mixture placed in a refrigerator for two days duringwhich time a solid separated from the solution. The mixture was filteredand the solid washed with a small amount of water. Recrystallizationfrom an ethanol-water mixture yielded a solid melting at C.

Calcd. for C H N O (percent): C, 36.4; H, 3.0; N, 28.3. Found (percent):C, 35.7; H, 3.05; N, 27.2.

Five (5) grams 3,S-dinitro-6-methyl-2-aminopyridine (prepared above) wasadded to 25 ml. glacial acetic acid and 50 ml. acetic anhydride and themixture refluxed for 4 /2 hours. After cooling to room temperature themixture was added to crushed ice and neutralized with solid sodiumbicarbonate. The resultant solution was extracted with ether, the etherlayers dried over anhydrous magnesium sulfate and the solvent removed bydistillation.

3 The residue which was a solid melted at 7276 C. The solid wasrecrystallized from ethanol-water yielding a solid melting at 106-107 C.

Calcd. for C H N O' (percent): C, 40.0; H, 3.33; N, 23.3. Found(percent): C, 39.2; H, 3.9; N, 23.03.

EXAMPLE 3 This example describes the preparation of 2,6-dimethyl-3-nitro-4-aminopyridine.

Four (4) grams 4-amino-2,6-dimethylpyridine was dissolved, withstirring, in 20 ml. concentrated sulfuric acid. The resultant mixturewas cooled to C. and then 2.68 ml. concentrated nitric acid slowlyadded, keeping the temperature between 10 C. and 5 C. The mixture wasthen stirred at 10 C. to 0 C. for one hour. The mixture was added tocrushed ice and made alkaline with an ammonia, ammonium carbonatesolution. The resultant solution was concentrated to half its volume ona steam bath under reduced pressure, at which time a yellow solidprecipitated from the solution. The mixture was cooled to 5 C. and thesolid removed by filtration, the solid washed with cold Water and driedin a vacuum oven at 60 C. The resultant solid melted at 210 C.

One (1) gram 2,6-dimethyl-4-nitroaminopyridine (prepared above) wasadded to ml. concentrated sulfuric acid and the resultant mixture heatedon a steam bath for 1 hour. The mixture was then added to crushed iceand made alkaline, to a pH 8, by the addition of ammonium hydroxide. Theresultant solution was placed in a refrigerator overnight during whichtime, 2,6-dimethyl-3-nitro- 4-aminopyridine precipitated as a buttcolored solid having a melting point of 135137 C.

Other compounds prepared according to the procedures outlined aboveinclude:

3-nitro-4-aminopyridine 5-nitro-2-aminopyridine3,S-dinitro-Z-aminopyridine 3 ,5 -dinitro-4-aminopyridine2-chloro-3-nitro-4-aminopyridine 2-chloro-3-nitro-6-aminopyridine2-chloro-3-nitro-6-acetamidopyridine 2-chloro-S-nitro-4-aminopyridine3chloro-5-nitro-6-phenylsulfonamidopyridine5-chloro-3-nitro-2-acetamidopyridine 6-chloro-3-nitro-2-aminopyridine6-chloro-S-nitro-Z-aminopyridine 2,6-dichloro-3-nitro-4-aminopyridineZ-iodo-3-nitro-4-aminopyridine 3-methyl-5-nitro-2-aminopyridine4methyl-3-nitro-2-aminopyridine 6-methyl-3 -nitro-2-aminopyridine6-methyl-5-nitro-2-aminopyridine 4,6-dimethyl2,4-nitro-2-aminopyridine6-n-butyl-3-nitro-2-aminopyridineS-trichloromethyl-3-nitro-2-aminopyridine4-allyl-3-nitro-2-aminopyridine 4-ethoxy-3-nitro-2-acetamidopyridine6-carboethoxy-3-nitro-2-aminopyridine S-nitro-Z-dipropylaminopyridine3-nitro-4-methanesulfonamidopyridine2-chloro-3-nitro-4-acetamidopyridinium hydrochloride2,6-dichloro-3-nitro-4-acetamido-N-methylpyridinium chloride3-nitro-4-acetamidopyridinium oxalate 3,5-dinitro-2-valeramidopyridine2-chloro-3-nitro-4-propylsulfonamidopyridine The herbicidal compositionsof this invention contain at least one active ingredient and a materialreferred to in the art as a herbicidal adjuvant in liquid or solid form.The herbicidal compositions are prepared by admixing the activeingredient with an adjuvant including diluents, extenders, carriers andconditioning agents to provide com-- positions in the form offinely-divided particulate solids,

granules, pellets, solutions and aqueous dispersions or emulsions.

Typical finely-divided solid carriers and extenders which can be used inthe herbicidal compositions of this invention include but are notlimited to talcs, clays, pumice, silica, diatomaceous earth, quartz,fullers earth, powdered cord, powdered wood, walnut flour, chalk,tobacco dust, volcanic ash and the like. Typical liquid diluents includebut are not limited to kerosene, Stoddard solvent, hexane, benzene,toluene, acetone, ethylene dichloride, xylene, alcohols, diesel oil,glycols and the like.

The herbicidal compositions of this invention, particularly liquids andwettable particles, usually contain as a conditioning agent one or moresurface-active agents in amounts sufiicient to render a givencomposition readily dispersible in water or in oil. By the termsurface-active agent" it is understood that wetting-agents, dispersingagents, suspending agents and emulsifying agents are included therein.

The term herbicidal compositions as used herein and in the appendedclaims is intended to mean not only compositions in a suitable form forapplication but also concentrated compositions which require dilution orextension with a suitable quantity of liquid or solid adjuvant prior toapplication.

The term plant system as used herein and in the appended claims meansgerminant seeds, emerging seedlings and established vegetation includingthe roots and above-ground portions.

EXAMPLE 4 The pre-emergent herbicidal activity of representativenitroaminopyridines of this invention is demonstrated as follows:

A good grade of top soil is placed in aluminum pans and compacted to adepth of to V2 inch from the top of the pan. A predetermined number ofseeds of each of several plant species are placed on top of the soil inthe pans. The seeds were covered with soil and the pan leveled. Theherbicidal composition is applied by spraying the surface of the toplayer of soil with a solution containing a suflicient amount of activeingredient to obtain a rate of application of 10 pounds per acre. Thepans are then watered from the bottom and placed on a wet sand bench andmaintained for approximately 14 days under ordinary conditions ofsunlight and watering. The plants are observed at the end ofapproximately 14 days and the results recorded. The herbicidal activityindex is based on the average percent germination of each seed lot. Theactivity index is converted to a relative numerical scale for the sakeof brevity and simplicity. The results are recorded in Table I.

The pre-emergent herbicidal activity used in the following example isdefined as follows.

Foxtall Crab grass Pigweed Soybean Wild buckwheat Tomato Sorghumrcmwmwmmweowwmw wwmwwweeeecnceweeu wwoawwwwwwwumw OI Nora-Compound (A),6-methyl-5-nitro-2-aminopyridine; compound (13), 2 chloro-ii-nitro fiacetamidopyridine; compound (0), 5-chl0r0-3- mtro-Z-acetamidopyndme.

EXAMPLE 5 This example demonstrates the post-emergent herbicidalactivity of representative nitroaminopyridines of this invention.

The active ingredient is applied in spray form to 14-day old specimensof the same plant species used in the pre-emergent tests above. Theherbicidal sprays are acetone-water solutions containing 0.50 activeingredient. The solutions are applied at a rate equal to approximatelypounds per acre of active ingredient. The treated plants are placed in agreenhouse and the efiects observed and recorded after approximately 14days. The results are recorded in Table II.

The pre-emergent herbicidal activity index used in this example is basedon the average percent injury of each plant species and is defined asfollows:

Numerical scale: Herbicidal activity As mentioned hereinbefore theherbicidal compositions of this invention comprise an active ingredientand one or more herbicidal adjuvants which can be solid or liquidextenders, carriers, diluents, conditioning agents and the like.Preferred herbicidal compositions containing the active ingredients ofthis invention have been developed so that the active ingredients can beused to the greatest advantage to modify the growth of plant systems insoil. The preferred compositions comprise certain wettable powders,aqueous suspensions, dust formulations, granules, emulsifiable oils andsolutions in solvents. In general these preferred compositions can allcontain one or more surface-active agents.

Surface-active agents which can be used in the herbicidal compositionsof this invention are set out, for example, in Searle U.'S. Pat.2,426,417, Todd US. Pat. 2,655,447, Jones US. Pat. 2,412,510 and LennerUS. Pat. 2,139,276. A detailed list of such agents is also set forth byI. W. McCutcheon in Soap and Chemical Specialties, November 1947, page8011 et seq, entitled Synthetic Detergents; Detergents and EmulsifiersUpto Date (1960), by J. W. McCutcheon, Inc., and Bulletin 15-607 of theBureau of Entomology and Plant Quarantine of the U.S.D.A. In generalless than 15 parts by weight of the surface-active agent is present per100 parts by weight of the herbicidal composition.

Wettable powders are water-dispersible compositions containing one ormore active ingredients, an inert solid extender and one or more wettingand dispersing agents. The inert solid extenders are usually of mineralorigin such as the natural clays, diatomaceous earth and syntheticminerals derived from silica and silicate. Examples of such extendersinclude kaolinites, attapulgite clay and synthetic magnesium silicate.

Preferred wetting agents are alkyl benzene and alkyl naphthalenesulfonates, sulfated fatty alcohols, amines or acid amides, long chainacid esters of sodium isothionate,

esters of sodium sulfosuccinate, sulfated or sulfonated fatty acidesters, petroleum sulfonates, sulfonated vegetable oils and ditertiaryacetylinic glycols. Preferred dispersants are methyl cellulose,polyvinyl alcohols, sodium lignin sulfonates, polymeric alkylnaphthalene sulfonates, sodium naphthalene sulfonate, polymethylenebisnaphthalenesulfonate and sodium N-methyl-N-(long chain acid)taurates.

The wettable powders compositions of this invention usually contain fromabout 5 to about parts of active ingredient, from about 0.25 to about3.0 parts of wetting agent, from about 0.25 to about 7 parts ofdispersant and from about 4.5 to about 94.5 parts of inert solidextender, all parts being by weight of the total composition. Whererequired from about 0.1 to 2.0 parts by weight of the solid inertextender can be replaced by a corrosion inhibitor or anti-foaming agentor both.

Aqueous suspensions are usually prepared by mixing together an aqueousslurry of water-insoluble active ingredient in the presence ofdispersing agents to obtain a concentrated slurry of very finely-dividedparticles. The resulting concentrated aqueous suspension ischaracterized by its extremely small particle size, so that when dilutedand sprayed coverage is very uniform.

Dusts are dense finely-divided particulate compositions which areintended for application to the soil in dry form. Dusts arecharacterized by their free-flowing and rapid settling properties sothat they are not readily wind-borne to areas where they are of novalue. Dusts contain primarily an active ingredient and a dense,free-flowing,

finely-divided particulate extender. However, their performance issometimes aided by the inclusion of a wetting agent such as those listedhereinbefore under wettable powder compositions and convenience inmanufacture frequently demands the inclusion of an inert, absorptivegrinding aid. Suitable class of grinding aids are natural clays,diatomaceous earth and synthetic minerals derived from silica orsilicate. Preferred grinding aids include attapulgite clay, diatomaceoussilica, synthetic fine silica and synthetic calcium and magnesiumsilicate.

The inert finely-divided solid extender for the dusts can be ofvegetable or mineral origin. The solid extenders are characterized bypossessing relatively low surface areas and are poor in liquidabsorption. Suitable inert solid extenders for herbicidal dusts includemicaceous talcs, pyrophyllite, dense kaolin clays, ground calciumphosphate rock and tobacco dust. The dusts usually contain from about0.5 to 99 parts active ingredient, 0 to 50 parts grinding aid, 0 to 3parts wetting agent and 1 to 99.5 parts dense solid extender, all partsbeing by weight based on the total weight of the dust.

The wettable powders described above may also be used in the preparationof dusts. While such wettable powders could be used directly in dustform, it is more advantageous to dilute them by blending with the densedust diluent. In this manner, dispersing agents, corrosion inhibitors,and anti-foam agents may also be found as components of a dust.

Emulsifiable oils are usually solutions of active ingredient inwater-immiscible solvents together with a surfactant. Suitable solventsfor the active ingredient of this invention include hydrocarbons andwater-immiscible ethers, esters or ketones. Suitable surfactants areanionic, cationic and non-ionic such as alkyl aryl polyethoxy alcohols,alkyl and alkyl aryl polyether alcohols, polyethylene glycol fattyesters, fatty alkyllol amide condensates, amine salts of fatty alcoholsulfates together with long chain alcohols and oil soluble petroleumsulfonates or mixtures thereof. The emulsifiable: oil compositionsgenerally contain from about 5 to 95 parts active ingredient, about 1 to10 parts surfactant and about 4 to 94 parts solvent, all parts being byweight based on the total weight of emulsifiable oil.

Granules are physically stable particulate compositions comprisingactive ingredient adhering to or distributed through a basic matrix ofan inert, finely-divided particulate extender. In order to aid leachingof the active ingredient from the particulate, a surfactant such asthose listed hereinbefore under wettable powders can be present in thecomposition. Natural clays, pyrophyllites and vermiculite are examplesof operable classes of particulate mineral extenders. The preferredextenders are the porous, absorptive, preformed particles such aspreformed and screened particulate attapulgite or heat expended,particulate vermiculite, and the finely-divided clays such as kaolinclays, hydrated attapulgite or bentonitic clays. These extenders aresprayed or blended with the active ingredient to form the herbicidalgranules.

The mineral particles which are used in the granular herbicidalcompositions of this invention usually have a size range of 10 to 100mesh, but preferably such that a large majority of the particles havefrom 14 to 60- mesh with the optimum size being from 20 to 40 mesh. Clayhaving substantially all particles between 14 and 80 mesh and at leastabout 80 percent between 20 and 40 mesh is particularly preferred foruse in the present granular compositions. The term mesh as used hereinmeans U.S. Sieve Series.

The granular herbicidal compositions of this invention generally containfrom about 1 part to about 30 parts by weight of nitroaminopyridine per100 parts by weight of clay and to about parts by weight of wettingagent per 100 parts by weight of clay. The preferred herbicidal granularcompositions contain from about 5 parts to about 25 parts by weight ofactive ingredient per 100 parts by weight of clay.

The herbicidal compositions of this invention can also contain otheradditaments, for example, fertilizers, other herbicides, pesticides andthe like, used as adjuvant or in combination with any of theabove-described adjuvants.

The compounds of this invention may be used in combination with knownherbicides in order to provide enhanced biological effectiveness. Theuse of various herbicides in combination at the time of a singleapplication or sequentially is common in practice. Herbicides which maybe used in combination with the compounds of this invention include butare not limited to: substituted phenoxyaliphatic acids such as2,4-dichlorophenoxyacetic acid; 2,4,S-trichlorophenoxyacetic acid;2-methyl-4-chlorophenoxyacetic acid and the salts, esters and amidesthereof; triazine derivatives, such as 2-chloro-4-ethylamino-6-isopropylamino s triazine; 2,4-bis(isopropylamino)-6- methoxy-s-triazineand 2-methylmercapto-4,6-bis(isopropylamino) s triazine; ureaderivatives such as 3-(3,4- dichlorophenyl) 1,1 dimethylurea and3-(m-trifluoromethylphenyl) 1,1 dimethylurea and3-(3,4-dichlorophenyl)-l-methoxy-l-methylurea; pyridylium derivativessuch as 1:1'-etl1ylene-2,2-dipyridylium dihalide; acetanilicles such asN-isopropyl-alpha-chloroacetanilide, and 2-chloro-2,'6"-diethyl-N-methoxymethyl acetanilide; acetamides such asN,N-diallyl-alpha-chloroacetamide, carbamates such asethyl-N,N-di-n-propylthiolcarbamate, and 2,3-dichloroallyldiisopropylthiolcarbamates; substituted uracils such asS-bromo-3-sec-butyl-6-methyluracil, substituted anilines such asN,N-dipropyl-alpha,alpha,alphatrifluoro 2,6 dinitro-p-toluidine;pyridazone derivatives such asS-amino-4-chloro-2-phenyl-3-(2H)-pyridazinone, and the like.

Fertilizers useful in combination with the active ingredients include,for example ammonium nitrate, urea and superphosphate. Other usefuladditaments include materials in which plant organisms take root andgrow such as compost, manure, humus, sand and the like.

When operating in accordance with the present inven tion, effectiveamounts of the nitroaminopyridines are dispersed on or in the soil orplant growth media and applied to plant systems in any convenientfashion. Application to the soil or growth media can be carried out bysimply mixing with the media, by applying to the surface of the soil andthereafter dragging or discing into the soil to the desired depth, or byemploying a liquid carrier to accomplish the penetration andimpregnation. The application of liquid and particulate solid herbicidalcompositions to the surface of soil or to plant systems can be carriedout by conventional methods, e.g., powder clusters, boom and handsprayers and spray dusters. The compositions can also be applied fromairplanes as a dust or a spray because of their effectiveness at lowdosages. In a further method, the distribution of the active ingredientsin soil can be carried out by admixture with the water employed toirrigate the soil. In such procedures, the amount of water can be variedwith the porosity and water holding capacity of the soil to obtain thedesired depth of distribution of the active ingredient.

The application of an effective or herbicidal amount of thenitroaminopyridines to the soil or growth media or plant systems isessential and critical for the practice of one embodiment of the presentinvention. The exact amount of active ingredient to be employed isdependent upon the response desired in the plant as well as such otherfactors as the plant species and stage of development thereof, thespecific soil and depth at which the active ingredients are distributedin the soil and the amount of rainfall as well as the specificnitroaminopyridine employed. In foliar treatment for the control ormodification of vegetative growth, the active ingredients are applied inamounts from about 1 to about 50 or more pounds per acre. Inapplications to soil for the control or modification of the growth ofgerminant seeds, emerging seedlings and established vegetation, theactive ingredients are applied in amounts from about 1 to about 50 ormore pounds per acre. In selective pre-emergent herbicidal applicationsthe nitroaminopyridines are usually applied in amounts from 0.1 to 5pounds per acre. It is believed that one skilled in the art can readilydetermine from this specification, including examples, the applicationrate for any specific situation.

The terms soil and growth media are employed in the presentspecification and claims in their broadest sense to be inclusive of allconventional soils as defined in Websters New International Dictionary,Second Edition, Unabridged (1961). Thus, the terms refer to anysubstance or media in which vegetation may take root and grow, and areintended to include not only earth but compost, manure, muck, humus,sand and the like, adapted to support plant growth.

While the illustrative embodiments of the invention have been describedhereinbefore with particularity, it will be understood that variousother modifications will be apparent to and can readily be made by thoseskilled in the art without departing from the scope and spirit of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and description set forthherein but rather the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present inventionincluding all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

What is claimed is:

1. Method which comprises applying to plant systems a herbicidallyeffective amount of a nitroaminopyridine of the formula wherein R isalkyl having a maximum of four carbon atoms, R is acyl having a maximumof six carbon atoms, alkylsulfonyl having a maximum of four carbon atomsand phenylsulfonyl; n and x are each integers of 1 to 2; provided thatat least 1 of n or x is 2.

2. A method in accordance with claim 1 in which R, and phenylsulfonyl;i: and x are each integers of 1 to 2; is selected from the groupconsisting of gcyl having as pr oviticq thttt gt lcqst l of n 01 is 2.maximum of four carbon atoms and p'hcnylsulfonyl.

3. A herbicidal composition comprising a herbicidally e crcnc Citedeffective amount of s nitroaminopyridinc of the formuln 5 UNITED STATESP N 3,495,969 2/ 1970, Driscoll 71--94 3,547,935 12/1970 Dichl et a].71--94 (R) NHR, 3,630,714 12/1971 Sclms 71-94 N r 10 3,535,328 10/1970Ziclinski a." 7194 JAMES o. THOMAS, JR., Primary Examiner whercm R 18alkyl having a maximum of four carbon atoms, R, is acyl having a maximumof six carbon atoms, US. Cl. X.R,

alkylsulfonyl having a maximum of four carbon atom: 71-92, 93

